mirror of https://github.com/longtai-cn/hippo4j
wulang
3 years ago
parent
71e96fb9bc
commit
db8ac51f4b
@ -0,0 +1,105 @@
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/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package cn.hippo4j.common.toolkit;
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/**
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* number util
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*/
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public class NumberUtil {
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public static boolean isNumber(CharSequence str) {
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if (StringUtil.isBlank(str)) {
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return false;
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}
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char[] chars = str.toString().toCharArray();
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int sz = chars.length;
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boolean hasExp = false;
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boolean hasDecPoint = false;
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boolean allowSigns = false;
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boolean foundDigit = false;
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// deal with any possible sign up front
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int start = (chars[0] == '-' || chars[0] == '+') ? 1 : 0;
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if (sz > start + 1) {
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if (chars[start] == '0' && (chars[start + 1] == 'x' || chars[start + 1] == 'X')) {
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int i = start + 2;
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if (i == sz) {
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return false;
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}
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for (; i < chars.length; i++) {
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if ((chars[i] < '0' || chars[i] > '9') && (chars[i] < 'a' || chars[i] > 'f') && (chars[i] < 'A' || chars[i] > 'F')) {
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return false;
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}
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}
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return true;
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}
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}
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sz--;
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int i = start;
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while (i < sz || (i < sz + 1 && allowSigns && !foundDigit)) {
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if (chars[i] >= '0' && chars[i] <= '9') {
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foundDigit = true;
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allowSigns = false;
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} else if (chars[i] == '.') {
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if (hasDecPoint || hasExp) {
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return false;
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}
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hasDecPoint = true;
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} else if (chars[i] == 'e' || chars[i] == 'E') {
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if (hasExp) {
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return false;
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}
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if (!foundDigit) {
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return false;
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}
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hasExp = true;
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allowSigns = true;
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} else if (chars[i] == '+' || chars[i] == '-') {
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if (!allowSigns) {
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return false;
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}
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allowSigns = false;
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foundDigit = false;
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} else {
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return false;
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}
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i++;
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}
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if (i < chars.length) {
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if (chars[i] >= '0' && chars[i] <= '9') {
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return true;
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}
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if (chars[i] == 'e' || chars[i] == 'E') {
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return false;
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}
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if (chars[i] == '.') {
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if (hasDecPoint || hasExp) {
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return false;
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}
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return foundDigit;
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}
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if (!allowSigns && (chars[i] == 'd' || chars[i] == 'D' || chars[i] == 'f' || chars[i] == 'F')) {
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return foundDigit;
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}
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if (chars[i] == 'l' || chars[i] == 'L') {
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return foundDigit && !hasExp;
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}
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return false;
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}
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return !allowSigns && foundDigit;
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}
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}
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